Doctor for paper-making machinery



Oct 18, w VlCKERY DOCTOR FOR PAPER MAKING MACHINERY Filed May 3, 1930 2 Sheets-Sheet 1 Q O i" '7 /f// z -/r/ .mzm 1 10' so nnnuunfin a 3 5 Ina-m 1932- F. w. VICKERY DOCTOR FOR PAPER MAKING MACHINERY Sheets-Sheet 2 Filed May 3. 1950 Patented Oct. 18,1932

UNITED, STATES PATENT OFFICE FREDERICK WILLIAM 'V'IGKEBY, 01'. LONDON, ENGLAND, ASSIGNOB: VICKEBY INCORPORATED, A" CORPORATION 01 MASSACHUSETTS noc'roa r03 PAPER-MAKING imomnnny Application filed May 3, 1980, Serial No. 449,442, and in (treat Britain Iay 14, 1829.

T To prevent accumulation of adherent material on the-press rolls, calender rolls and other rolls of paper making machinery, and in some cases to guide the paper web, such rolls are commonly fitted with doctors. In the older forms of doctor a plane resilient blade is fastened directly toa rigid carrier extending across the paper-making machine and commonly pivoted in it. In modern doc- 19 tors to ensure good contact of the edge of p the blade Withthe roll notwithstanding displacements of the roll, wear of its surface and other irregularities, it is usual to carry the blade upon a resilient support, such as a spring plate or. a series of spring fingers, ex-

tending in the plane of the blade between it 7 and the usual rigid carrier.

One purpose of the present invention is to lmprove doctoring and obtain a longer life 20 of blade by setting the doctoring edge of the blade, that is to say, the portion of the blade next the roll-at a large angle to the roll, say from 45 to nearly radial, supporting it so that it can adapt itself to the roll, and obviating the risks of chattering and of damage to the roll to which such a position gives rise.

A further purpose of the invention is to enable a blade having its doctoring edge set at a large angle to the roll to be accommodated within the limited space of'a vacuum chamber or a heated dryi chamber;

Another purpose 0' the invention isto facilitate the initial adjustment of the doctor carrierso that the doctor may bear upon the roll with uniform pressure throughout its length without initial deformation of the 1 blade or the resilient parts of its support;

, To these ends the invention includes a doctor having'the doctoring edge of its blade 7 set at a large angleto the roll, andthe blade supported from a carrier pivoted on an axis lying vWell-out of the plane of the doctoring edge and between that plane and the roll.

-In some forms the invention consists in a doctor the blade-of which is attached tothe rigid pivoted carrier by-anjintermediate stifi' support of angle section,.one limb of which is adapted for attachment to the carrier and the other to receive a blade to the roll.

In another aspect the invention comprises a doctor blade set at a large angle to the roll and abutting by its rear cedge upon a stifi 5 support of angle section which has a surface slightly inclined to the working position of the blade and towards which the blade is spring pressed so that it rests on the straight "edge of the support when not resting on the oo In yet another aspect the invention lies 1n so supporting a blade at a large angle to the roll that it can move against spring action in two directions; or btherwise stated, in the U combination of a blade with a stiff carrier and with springs bearing on the outer face of the blade and upon its rear edge.

Constructions embodying the invention are shown in the accompanying drawings.-

Figure 1.is a sectional elevation and Figure 2 an elevation at right angles of a doctor blade clamped betweena bent resilient support and a bent back plate.

Figure 3 is a sectional elevatlon'of a sim- 1i ilar construction with/the addition of other springs bearing on the edge of the blade.

=Figure 4 is a sectional elevation and Figure 5 an elevation atright angles in section on the line V-V of Figure 4 ofafl modified construction providingfor spring pressure on the rear edge of the blade,

Figure 6 is a sectional elevation of a modification of Figure 4.

Figure 7 is a sectional elevation of a doctor with a curved blade; 1

InFigures 1 and 2, the usual rigid doctor carrier extending across the paper-making machine is shown at 1. A kgsual it is made to. hinge on pivots 2 at eac side of the machine and is pressed downward by springs or gravity, not shown, toexert the necessa pressure on the. doctor blade 3. The blade is set at a large angle held between a bent spring plate 4 preferably made in several short lengths, or a series or ing as to afford no firm line of reference for 'endwise and leaving a gap Both back-plate and spring are clamped upon the carrier 1 by a clamping strip 6. The rear edge of the doctor blade may abut upon the resilient support 4 or upon a rabbet or shoulder formed in the back-plate 5 as shown. A back-plate of the form shown in Figure 1, or of the forms described below may conveniently be made by extrusion. It will be understood that when working the doctor blade stands at a small angle to the limb of the back-plate on' which its rear edge always abuts, and is pressed by the springs 4 upon the roll. When the doctor is lifted from the roll by raising the pivoted carrier 1, the springs 4 press the blade 3 into surface contact with the back-plate, and the straight edge of the back-plate serves as a line of reference defining the position of the blade and therefore of its edge. Hence notwithstand ing that the blade can readily yield while working, when not working its edge is firmly supported, and the support can readily be adjusted to bring the edge into exactly the proper relation with the roll, so that when the doctor is lowered upon the roll the edge will bear with uniform pressure throughout its length without initial irregular deformationof the springs. Such adjustment is not easy where the resilient support of the blade makes the blade, when lifted, so readily yieldadjustment.

If additional spring pressure is desired upon the rear edge of the blade, leaf springs such as shown at 7 in Figure 3 may be attached to the back-plate 5 and project through openings 8 in it. Still greater pressure may be obtained by the arrangement shown in Fi res 4 and 5, where a recess 9 is formed in the back-plate 5 to receive a number of bent springs 10, between which rigid abutments are formed for instance by blocks 11 orthe curled ends of the springs. The resilient support 4 is removed in Figure 5 and a part of the back-plate cut away to make these springs and blocks visible. The strength of the springs should be so adjusted that in normal working the rear edge of the blade 3 compresses the springs sufliciently to rest against the solid blocks 11, but if through wear or displacement a part of the. surface of'the roll is further removed from the doctor carrier, the springs 10 will press the blade out so that it maintains firm contact with the roll throughout its length. To facilitate the removal of accumulated dbris when the blade is taken out'the intermediate support may be made in two parts, the part 12 sliding out 4 and back-plate 5.

Alternatively the recess?) may be formed with a slanti'ng rear edge, and filled by a tapered metal sp ing pressed endwise by a spring. The slanting surface of the recess.

and of the strip'will cause the blade to be between springs thrust outward when the strip moves longitudinally under the pressure of its spring.

Figure 6 shows a construction generally similar to Figure 4 save that the rubber strip 24 replaces the spring plate or fingers 4, and the member 5 is modified to receive this strip in a channel 25.

A art of the advantages of the invention may attained by the simple construction shown in Figure 7. This form of the invention is described and claimed in my co-pending divisional application, Serial No. 625,074, filed July 27, 1932. Here the doctor blade 13 is itself curved in section so that its work ing edge stands at alarge angle to the roll, while a plane of that edge is far from passing through the axis of the pivots 2. The blade is frictionally held at its rear or outer edge by a clamping strip 14.

It will be observed that a blade shaped as shown can wear to a considerable extent without much changing its angle of contact with the roll. The construction is also compact and capable of accommodation in the limited space of a vacuum chest. The curved section of the blade makes it stiff longitudinally, so

'it upon a roll and towards surface contact with said support, and upon the rear edge of said blade to press it in its own plane towards the roll.

2. In a doctor the combination of a rigid support of angle section carried on pivots, said support having one part inclined at a relatively small angle to the roll and directed towards the axis of its pivots and the other part inclined at a relatively steep angle to the roll, a blade having its rear edge contacting with-the latter part, and resilient means pressing said blade upon the roll and towards surface contact with said support.

3. A doctor comprising a blade edge setat a largeangle to the roll, a rigid support, and resilient means permitting and resisting movement of said edge in two directions relatively to said support. -4. In a doctor the combination of a blade standing at a large angle to the roll, a rigid carrier pivoted on an axis between the plane of the blade and the roll and having a surface on which the rear edge of said blade rests slightly inclined to the working position of said blade, and springs pressing said blade upon the roll and towards surface contact with said surface.

5. Ina doctor the combination of a back plate of angle section, a blade having its rear edge abutting on said back plate, a bent resilient support secured on said back plate, and gripping the blade between itself and said ack plate, and means bearing on the rear edge of said blade to roll.

6. In a doctor the combination of a stiflz' support of angle section, a blade having its rear edge abutting on said support, spring means attached to said support hearing on the outer face of said blade, and other spring means interposed between a part of said support and the rear edge of said blade.

7. In a paper-making machine the combination with a roll of a doctor blade co-operating with said roll and inclined in the direction of travel of the roll at a large angle to the roll, a rigid pivoted carrier supporting said blade, the plane containing the axis on which said carrier pivots and the line of contact of blade and roll being at a relatively small angle to the roll, and resilient means pressing said blade-towards said roll transversely to its own plane.

8. In a doctor the combination with a rigid pivoted carrier extending across the papermaking machine, of an intermediate stifl support having mutually inclined faces one of said faces being fastened in contact with said carrier, a blade, and spring means pressing said blade towards surface contact with the other face.

In testimony whereof I have signed my name to this specification.

FREDERICK WILLIAM VICKERY.

press it towards the 

